<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>++\--在前在后的区别</title>
    <script type="text/javascript">
        var number1 = 9;
        //++在后，先拿变量去用，用完了再自加
        document.write("<br/>number1: "+(number1++));
        //++在前，先自加，再拿变量去用
        document.write("<br/>number1: "+(++number1));
    </script>
</head>
<body>

</body>
</html>